The deep-sea as a final global sink of semivolatile persistent organic pollutants? Part I: PCBs in surface and deep-sea dwelling fish of the North and South Atlantic and the Monterey Bay Canyon (California),

Description

The understanding of the global environmental multiphase distribution of persistent organic pollutants (POPs) as a result of the physico-chemical properties of the respective compounds is well established. We have analysed the results of a vertical transport of POPs from upper water layers (0-200 m) to the deepwater region (>800 m) in terms of the contamination of the biophase in both water layers. The contents of persistent organochlorine compounds like polychlorinated biphenyls (PCBs) in fish living in the upper water layers of the North Atlantic and the South Atlantic, and at the continental shelf of California (Marine Sanctuary Monterey Bay and its deep- sea Canyon) are compared to the levels in deep-sea or bottom dwelling fish within the same geographic area. The deep-sea biota show significantly higher burdens as compared to surface-living species of the same region. There are also indications for recycling processes of POPs - in this case the PCBs - in the biophase of the abyss as well. It can be concluded that the bio- and geo phase of the deep-sea may act similarly as the upper horizons of forest and grasslands on the continents as an ultimate global sink for POPs in the marine environment. (C) 2000 Elsevier Science Ltd., Cited By (since 1996):56, Ecology,
Fish and Fisheries, CODEN: CMSHA, ,

Temperature measured at the Monterey Inner Shelf Observatory (MISO) in southern Monterey Bay reveals frequent solitons and semidiurnal internal tidal bores (ITBs). A field study was undertaken to determine whether these features originate offshore and propagate shoreward over the continental shelf, and to characterize their evolution as they propagate. We developed a new survey method of using an autonomous underwater vehicle (AUV) to tightly track the thermocline along a 4.5 km transect, repeated 18 times over 18 hours, thereby measuring the internal-wave induced isotherm displacement at very high resolution. AUV measurements were compared with measurements at MISO, which is closer to shore. Internal waves of various scales were captured. An ITB of amplitude greater than 20 m propagating shoreward from the outer bay was the dominant feature. Rapid changes in stratification, possibly due to horizontal advection, were also observed. Technical challenges, advantages, and future improvements of this new AUV survey method are discussed. This study demonstrates that AUVs are efficient tools for surveying internal tidal waves., Cited By (since 1996):3, ,

Effects of iron, manganese, copper, and zinc enrichments on productivity and biomass in the subarctic Pacific,

Description

Natural plankton populations from subarctic Pacific surface waters were incubated in 7-d experiments with added concentrations of Fe, Mn, Cu, and Zn. Small additions of metals (0.89 nM Fe, 1.8 nM Mn, 3.9 nM Cu, and 0.75 nM Zn) were used to simulate natural perturbations in metal concentrations potentially experienced by marine plankton. Although the controls indicated little growth, increases in phytoplankton productivity, Chl a, and cell densities were dramatic after addition of 0.89 nM Fe, indicating that it may limit the rates of algal production in these waters. Similar increases were observed in experiments with 3.9 nM Cu added. The Cu effect is attributed to a decrease in the grazing activities of the microzooplankton (ciliates) and increases in the rates of production. Mn enrichment had its greatest effect on diatom biomass, whereas Zn enrichment had its greatest effect on other autofluorescent organisms. Natural systems may be affected as follows: natural levels of Fe and Cu may influence phytoplankton productivity and trophic structure in open-ocean, high-nutrient, low-biomass systems; rates of net production are not limited by one micronutrient alone. -from Author, , , ,

Growth rate and potential climate record from a rhodolith using 14C accelerator mass spectrometry,

Description

, , , Rhodoliths, free-living calcareous red algae, create large and diverse habitats worldwide. Although these plants
are abundant and ecologically important, little is known about their growth rate. We determined the growth rate for
an individual rhodolith, Lithothamnium crassiusculum, from the southern Gulf of California through 14C analysis
using accelerator mass spectrometry (AMS) to be 0.6 mm yr21. This growth rate suggests large L. crassiusculum,
which have been found with radii in excess of 6 cm, may live over 100 yr. Declines in the D14C record associated
with the large El Nin˜o events of 1957, 1982, and 1992 indicate 14C analysis may lead to identification of important
climate events in the more distant past. The ability to determine changes in past ocean circulation related to changes
in past climatic conditions through AMS 14C analysis of rhodoliths would increase the geographic range of available
climate records from the tropical oceans to the entire global ocean and potentially allow for the determination of
past climate conditions from rhodoliths in fossil beds., ,

The natural diet of Pleurobranchaea californica was studied in Monterey Bay, California. Specimens were collected from 29 January to 9 November 1992, at depths of 30-100 m using an otter trawl and an interfacial trawl. Three hundred fifty-six individuals were collected and ranged in size from 0.01-411 g with most of the individuals weighing between 1.0 and 50 g. The gut contents were examined and 16 different taxa were identified. Thirty-three percent of the guts were empty. Many animals had sediment in their guts, which was presumed to be a result of their ingesting or attempting to ingest prey. Pleurobranchaea californica was found to be a euryphagic predator with pronounced cannibalism. Individual Index of Relative Importance values showed that opisthobranchs made up the largest portion of the diet. The opisthobranchs in the diet included Pleurobranchaea californica (as prey), Armina californica, and Aglaja sp. The diets were similar for specimens of P. californica collected at all depths, but did change depending upon the season in which the animals were collected., Cited By (since 1996):4, Invertebrates, ,

Evolution of Macrocystis spp. (Phaeophyceae) as determined by ITS1 and ITS2 sequences

Description

Macrocystis (Lessoniaceae) displays an antitropical distribution, occurring in temperate subtidal regions along western North America in the northern hemisphere and throughout the southern hemisphere. We used the noncoding rDNA internal transcribed spacer regions (ITS1 and ITS2) to examine relatedness among (1) Macrocystis and several genera of Laminariales, (2) four species of Macrocystis (M. integrifolia Bory from the northern hemisphere, M. angustifolia Bory and M. laevis Hay from the southern hemisphere, and M. pyrifera [L.] C. Ag. from both hemispheres), and (3) multiple clones of several individuals. Of the taxa included in our phylogenetic analysis, the elk kelp, Pelagophycus porra (Lem.) Setch., was the sister taxon to Macrocystis spp. Macrocystis individuals from the southern hemisphere (representing three species) formed a strongly to moderately supported clade, respectively, when the ITS1 and ITS2 sequences were analyzed separately. No distinction was detected between the two species in the northern hemisphere. Thus, Macrocystis may be a monospecific genus (M. pyrifera). A northern-hemisphere-to-southern-hemisphere pattern of dispersal was inferred, because northern-hemisphere individuals were more diverse and displayed paraphyletic clades, whereas southern-hemisphere individuals were less diverse and formed a monophyletic clade. High intraindividual variation in ITS1 sequences was observed in one individual from Santa Catalina Island (CA), suggesting very recent and rapid mixing of genotypes from areas to the north and Baja California (Mexico) or introgressive hybridization with Pelagophycus., Cited By (since 1996):67, Seaweeds, CODEN: JPYLA

Expressions of 1976-1977 and 1988-1989 regime shifts in sea-surface temperature off Southern California and Hawai'i,

Description

Sea-surface temperatures off southern California from Scripps Pier and from Koko Head, Hawai'i, were examined to determine what impact regime shifts that occurred in 1976-1977 and 1988-1989 had on environmental conditions at each location. Cumulative sums were employed to enhance the detection process. The cumulative sum time histories revealed major turning points at both locations at the time of the 1976-1977 event. At both locations, increases in temperature were indicated, consistent with the phase change in the Pacific Decadal Oscillation that took place at that time. The cumulative sums also indicated major turning points at both locations during the 1988-1989 event. A new procedure called the method of expanding means was employed to determine the long-term impact of these events. By comparing means before and after a given event it is possible to observe the magnitude of the change and to what extent it is sustained. For the 1976-1977 regime shift, temperatures increased rapidly and remained consistently higher, by ∼1°C for 2-3 yr at Scripps Pier. This increase occurred over a period of approximately 7 months and accounts for more than half of the total warming that has occurred at that location since 1920. At Koko Head, a similar response was observed with a sustained increase of approximately +0.5°C. The oceanic response to the 1988-1989 event was quite different. At Scripps Pier, temperatures before and after this event did not show any tendency to converge to significantly different values out to periods of 2-3 yr. At Koko Head, mean temperatures did converge to slightly different values after 1 yr, with mean values being consistently lower after this event (∼-0.4°C). It was shown that in some cases changes associated with these events could be identified in the original data, but without the help of cumulative sums, it is usually not possible to make a clear distinction between changes of interest and other sources of variability. Finally, decorrelation time scales for the records at both locations were estimated and found to be on the order of a year, implying spatial scales that are at least synoptic (tens to hundreds of kilometers)., Cited By (since 1996):1, ,

From October 1997 to May 2001, the gastrointestinal tracts from 162 beach-cast southern sea otters Enhydra lutris nereis were examined for helminth parasites and associated lesions. Carcasses were collected opportunistically in central California between Pt. San Pedro and Pt. Arguello. The primary goals of this study were to examine spatial and temporal variability in mortality due to parasite infection, identify factors associated with increased risk of infection, and illustrate the process of intestinal perforation by Profilicollis spp. Two genera and 4 species of acanthocephalans (Profilicollis altmani, P. kenti, P. major, Corynosoma enhydri) were found in 46.3% (Profilicollis spp.) and 94.4% (C. enhydri) of the carcasses examined. Three species of Digenea (Microphallus pirum, M. nicolli, Plenosoma minimum) were found in 47% of carcasses, at times in massive numbers (>3000 per cm2). This is the first report of the latter 2 species from the sea otter. Mortality resulting from infection by Profilicollis spp. occurred in 13.0% (n = 21) of sampled carcasses, either directly, due to perforation of the intestinal wall and peritonitis (9.9%, n = 16), or indirectly, due to inhibition of host nutrient uptake or depletion of host energy reserves to fight chronic infections (3.1%, n = 5). The most massive infections (<8760 parasites), and all cases of intestinal perforation occurred in carcasses infected by P. altmani and/or P. kenti. Mortality due to infection by Profilicollis spp. occurred more frequently among juvenile and old-adult females (χ2 = 17.479, df = 9, p = 0.045) from sand and mixed habitats in Monterey and Santa Cruz in the north of the sea otter range (χ2 = 9.84, df = 4, p = 0.045). Spatial differences in sea otter mortality coincided with the relative distributions of Profilicollis altmani, P. kenti, and P. major, and may reflect differences in sea otter diet, or differences in intensity of infection in intermediate hosts. Mortality rate due to infection by Profilicollis spp. decreased between 1998 and 2001, though differences were not significant (χ2 = 3.983, df = 3, p = 0.40), and may vary on multi-year cycles due to environmental factors such as density of definitive hosts (e.g. the surf scoter Melanitta perspicillata), or El Niño. Corynosoma enhydri did not cause significant damage to the intestine of the host, even when present in great numbers., Cited By (since 1996):9, CODEN: DAORE, , , Downloaded from: www.int-res.com/articles/dao2003/53/d053p077.pdf (9 June 2014).,

System of quasi-zonal jets off California revealed from satellite altimetry,

Description

A discrete wavelet transform was applied to satellite altimetry data for the period 1992-2007 off California to decompose the SSH signal into inter-annual, annual, semiannual and shorter period components. For the lowest frequency (inter-annual) component, a system of alternating quasi-zonal jets was detected. The jet system was delineated by a north-south series of quasi-zonal bands of co-rotating eddies; that is, the eddies were embedded in a shearing zonal flow. The direction of eddy rotation alternated between adjacent bands. The temporal behavior of the jet system showed the existence of quasi-stationary states and transitions between them. Observed non-linear effects of the evolution of the jets included southward drift at about 0.2 cm sec -1, deviations of the jets from the zonal direction, and re-forming of the jet system through decay and merging of eddy chains. Copyright 2009 by the American Geophysical Union., Cited By (since 1996):6, Oceanography, Art. No.: L03609, CODEN: GPRLA, , , Downloaded from:http://onlinelibrary.wiley.com/doi/10.1029/2008GL036327/pdf (16 June 2014).

Movements and population structure of humpback whales in the North Pacific,

Description

Despite the extensive of photographic identification methods to investigate humpback whales in the North Pacific, few quantitative analyses have been conducted. We report on a comprehensive analysis of interchange in the North Pacific among three wintering regions (Mexico, Hawaii, and Japan) each with two to three subareas, and feeding areas that extended from southern California to the Aleutian Islands. Of the 6,413 identification photographs of humpback whales obtained by 16 independent research groups between 1990 and 1993 and examined for this study, 3,650 photographs were determined to be of suitable quality. A total of 1,241 matches was found by two independent matching teams, identifying 2,712 unique whales in the sample (seen one to five times). Site fidelity was greatest at feeding areas where there was a high rate of resightings in the same area in different years and a low rate of interchange among different areas. Migrations between winter regions and feeding areas did not follow a simple pattern, although highest march rates were found for whales that moved between Hawaii and southeastern Alaska, and between mainland and Baja Mexico and California. Interchange among subareas of the three primary wintering regions was extensive for Hawaii, variable (depending on subareas) for Mexico, and low for Japan and reflected the relative distances among subareas. Interchange among these primary wintering regions was rare. This study provides the first quantitative assessment of the migratory structure of humpback whales in the entire North Pacific basin., Cited By (since 1996):60, CODEN: MMSCE, ,

Copper titrations were conducted at sea with differential pulse anodic stripping voltammetry to examine the degree to which copper was associated with organic ligands. Greater than 99.7% of the total dissolved copper in surface waters of the central Northeast Pacific shallower than 200 m was estimated to be associated with strong organic complexes. Below 200 m, increasing proportions of inorganic or labile copper species were observed. At middepths (1000 m), about 50-70% of the total dissolved copper was in the organically complexed form. Whereas total copper varies by a factor of only three from the surface to middepths (0.6-1.8 nM), copper complexation gives rise to extremely low cupric ion activities in surface waters ({Cu2+} = 1.4 × 10-4 M) and higher values at middepth ({Cu2+} = 10-11 M) -a variation of three orders of magnitude., Cited By (since 1996):208
Oceanography, ,